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February 2006 
For years, watermelon growers have
planted pollinators in separate rows, thinking honeybees traverse
the field from right to left and left to right.
But some watermelon growers - particularly those growing seedless
watermelons or triploids - are planting the pollinators within the
row, betting the pollinating bees travel up and down the row.
Bob Dyer is one such grower
"I haven't done any scientific
studies tracking the bees but I've watched the bees and have talked
with beekeepers and they go up and down the rows. They work in a
straight line," says Dyer who grows triploids in Mexico and
throughout the United States.
Closer to the
flower
Planting pollinators in the row brings the bees closer to the flower.
By working the row, honeybees don't have to jump the row to alight on
the blossoms.
They just follow the row's
plant spacing, which is less than half of between-the-row spacing.
So far, it's paying off
"By planting pollinators in the row we're seeing an earlier
pollination and an earlier fruit  set," says Dyer who - depending
on the growing area - sometimes plants a pollinator every second plant
in the row. "Like any other crop, the earlier the fruit set, the
earlier the harvest, and the earlier you have something to sell."
"Early fruit set is particularly important in Mexico where you're
making crops in 60 days," says Dyer, owner of Growers Select
Produce, Inc. in Mission, Texas.
Triploids -
all female
 Triploids
are a unique challenge for growers. Industry standards like
Millionaire
(right) and
Millennium
(left), by Harris Moran Seed Company, produce male and female
flowers but the male flowers only produce sterile pollen.
"When it's seedless watermelon you have to have the pollen to
pollinate them because they're mostly all females ? there's no
pollen," explains Dyer. "You will get some pollination
from the wind but not enough."
That's where the bees come in
"The bees work linearly. Where you have a row of seedless and a row of pollinators and the young plant starts to put out the first bloom they're still at least 80 inches away from the rows. If you have pollinators in the row they're only 30 inches away. The bee is traveling up and down the row, then he's more likely to jump from one plant to the next going down the row."
Beekeeper Clyde Frings agrees. He says there is no mystery as to the pattern of the bees' flight. The California beekeeper, who works with many triploid watermelon growers, says "It's up and down the rows." Maximum speed: 10 miles an hour. Range: 2 miles a day. And they always return to the hive.
In search of the perfect pollinator
One drawback of in-the-row pollinators is with harvesting. Because the pollinator plant usually produces fruit - commodity-type fruit - harvesters must be trained at the difference between pollinator fruit and high-value marketable fruit.
Typically, triploids produce round to slightly blocky fruit. Pollinators used in North America typically produce longer fruit.
One way to minimize this harvesting complication is by producing a pollinator that produces little or no fruit yet produces an enormous amount of pollen. Not only would harvesting complications be minimized, but less pollinators would be needed in the row and in the field.
"We're asking for an all male plant that produces no fruit," says Dyer. "That way we could plant maybe one every five plants. We're also asking for a tall plant - one that doesn't get choked out by the seedless plant and is more accessible to the bees."
Harris Moran investigating
Bill Copes, watermelon breeder with Modesto, CA-based Harris Moran, is working on something similar in his test plots.
"Even one pollinator in every four plants in the row means that 25% of your field is dedicated to producing pollen instead of producing triploid watermelons. We're experimenting with a special plant that produces tiny fruit yet produces a prolific amount of pollen. This would allow the grower to dedicate more of his field for the production of seedless fruit."
Less pollinators mean more fruit. And more fruit means more profits for the grower.
.
"The bottom line is growers are always looking for ways to squeeze more profit out of each acre," says Copes. "We realize that. And that philosophy has been a cornerstone of our breeding program."
But until the industry creates the perfect pollinator plant, growers like Dyer will continue to follow traditional methods. And the traditional method is quickly becoming in-the-row plantings. |
